To compile your wxWidgets c++ code and link with wxWidgets in build.rs files.
Supported targets: macos and x86_64-pc-windows-msvc
// Will compile all cpp files in my_cpp_folder.
// MyApp is name of my class extending wxApp
WX_CONFIG - path to wx-config script for non windows targets, if not set it will require wx-config to be present in $PATH
WX_DIR - on windows, path to wxWidgets folder. It assumes it was compiled static for x64 with VC.